<?php

if (! defined('BASEPATH'))
    exit('No direct script access allowed');

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package CodeIgniter
 * @author ExpressionEngine Dev Team
 * @copyright Copyright (c) 2006 - 2012 EllisLab, Inc.
 * @license http://codeigniter.com/user_guide/license.html
 * @link http://codeigniter.com
 * @since Version 2.0
 * @filesource
 *
 */
    
// ------------------------------------------------------------------------

/**
 * CodeIgniter Memcached Caching Class
 *
 * @package CodeIgniter
 * @subpackage Libraries
 * @category Core
 * @author ExpressionEngine Dev Team
 * @link
 *
 */
class CI_Cache_file extends CI_Driver
{

    protected $_cache_path;

    /**
     * Constructor
     */
    public function __construct ()
    {
        $CI = & get_instance();
        $CI->load->helper('file');
        
        $path = $CI->config->item('cache_path');
        
        $this->_cache_path = ($path == '') ? APPPATH . 'cache/' : $path;
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Fetch from cache
     *
     * @param
     *            mixed unique key id
     * @return mixed on success/false on failure
     */
    public function get ($id)
    {
        if (! file_exists($this->_cache_path . $id)) {
            return FALSE;
        }
        
        $data = read_file($this->_cache_path . $id);
        $data = unserialize($data);
        
        if (time() > $data['time'] + $data['ttl']) {
            unlink($this->_cache_path . $id);
            return FALSE;
        }
        
        return $data['data'];
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Save into cache
     *
     * @param
     *            string unique key
     * @param
     *            mixed data to store
     * @param
     *            int length of time (in seconds) the cache is valid
     *            - Default is 60 seconds
     * @return boolean on success/false on failure
     */
    public function save ($id, $data, $ttl = 60)
    {
        $contents = array(
                'time' => time(),
                'ttl' => $ttl,
                'data' => $data
        );
        
        if (write_file($this->_cache_path . $id, serialize($contents))) {
            @chmod($this->_cache_path . $id, 0777);
            return TRUE;
        }
        
        return FALSE;
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Delete from Cache
     *
     * @param
     *            mixed unique identifier of item in cache
     * @return boolean on success/false on failure
     */
    public function delete ($id)
    {
        return unlink($this->_cache_path . $id);
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Clean the Cache
     *
     * @return boolean on failure/true on success
     */
    public function clean ()
    {
        return delete_files($this->_cache_path);
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Cache Info
     *
     * Not supported by file-based caching
     *
     * @param
     *            string user/filehits
     * @return mixed FALSE
     */
    public function cache_info ($type = NULL)
    {
        return get_dir_file_info($this->_cache_path);
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Get Cache Metadata
     *
     * @param
     *            mixed key to get cache metadata on
     * @return mixed on failure, array on success.
     */
    public function get_metadata ($id)
    {
        if (! file_exists($this->_cache_path . $id)) {
            return FALSE;
        }
        
        $data = read_file($this->_cache_path . $id);
        $data = unserialize($data);
        
        if (is_array($data)) {
            $mtime = filemtime($this->_cache_path . $id);
            
            if (! isset($data['ttl'])) {
                return FALSE;
            }
            
            return array(
                    'expire' => $mtime + $data['ttl'],
                    'mtime' => $mtime
            );
        }
        
        return FALSE;
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Is supported
     *
     * In the file driver, check to see that the cache directory is indeed
     * writable
     *
     * @return boolean
     */
    public function is_supported ()
    {
        return is_really_writable($this->_cache_path);
    }
    
    // ------------------------------------------------------------------------
}
// End Class

/* End of file Cache_file.php */
/* Location: ./system/libraries/Cache/drivers/Cache_file.php */